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add missing operators and fix precedences #34

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Merged
SpaceManiac merged 2 commits into from
Jun 17, 2025
Merged

add missing operators and fix precedences #34

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31472f4
add missing operators and fix precedences
ecioppettini Jun 16, 2025
313f8c4
re-introduce neg operator for unary -
ecioppettini Jun 17, 2025
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32 changes: 24 additions & 8 deletions starstream_compiler/src/ast.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -168,10 +168,13 @@ pub enum Expr {
NotEquals(Box<Self>, Box<Self>),
/// `a < b`
LessThan(Box<Self>, Box<Self>),
// TODO: GreaterThan, LessEq, GreaterEq
/// `a > b`
GreaterThan(Box<Self>, Box<Self>),
/// `a <= b`
LessEq(Box<Self>, Box<Self>),
/// `a >= b`
GreaterEq(Box<Self>, Box<Self>),
// Arithmetic operators
/// `-a`
Neg(Box<Self>),

@SpaceManiac SpaceManiac Jun 17, 2025

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Any particular reason to drop Neg? Wasm has a floating-point neg instruction, and integer neg is easy to implement as ~x + 1

@ecioppettini ecioppettini Jun 17, 2025

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Mostly because it was previously ~, and when I changed that I removed it. But it probably makes sense to keep it I guess.

So I added it back. I'm not really sure how much people actually use the unary negation in general though.

/// `a + b`
Add(Box<Self>, Box<Self>),
/// `a - b`
Expand All @@ -180,13 +183,26 @@ pub enum Expr {
Mul(Box<Self>, Box<Self>),
/// `a / b`
Div(Box<Self>, Box<Self>),
/// `a ** b`
Pow(Box<Self>, Box<Self>),
// TODO: Mod
/// `a % b`
Mod(Box<Self>, Box<Self>),
/// `-a`
Neg(Box<Self>),
// Bitwise operators
// TODO: BitNot, BitAnd, BitOr, BitXor, LShift, RShift
/// `~a`
BitNot(Box<Self>),
/// `a & b`
BitAnd(Box<Self>, Box<Self>),
/// `a | b`
BitOr(Box<Self>, Box<Self>),
/// `a ^ b`
BitXor(Box<Self>, Box<Self>),
/// `a << b`
LShift(Box<Self>, Box<Expr>),
/// `a >> b`
RShift(Box<Self>, Box<Expr>),
// Boolean operators
// TODO: Not
/// `!a`
Not(Box<Self>),
/// `a && b`
And(Box<Self>, Box<Self>),
/// `a || b`
Expand Down
73 changes: 55 additions & 18 deletions starstream_compiler/src/parser/mod.rs
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Original file line number Diff line number Diff line change
@@ -1,7 +1,7 @@
use crate::ast::*;
use ariadne::{Color, Label, Report, ReportKind};
use chumsky::{
pratt::{infix, left, prefix, right},
pratt::{infix, left, prefix},
prelude::*,
};

Expand Down Expand Up @@ -324,7 +324,7 @@ fn optionally_typed_bindings<'a>(
fn expr<'a>(
block_parser: impl Parser<'a, &'a str, Block, extra::Err<Rich<'a, char>>> + Clone + 'a,
) -> impl Parser<'a, &'a str, Expr, extra::Err<Rich<'a, char>>> {
let op = |c| just(c).padded();
let op = |c: &'static str| just(c).padded();

recursive(|expr_parser| {
let function_call = expr_parser
Expand Down Expand Up @@ -358,37 +358,74 @@ fn expr<'a>(
.or(block_expr(expr_parser, block_parser).map(Expr::BlockExpr));

atom.pratt((
prefix(4, op('!'), |_, atom, _| Expr::Neg(Box::new(atom))),
infix(right(3), op('^'), |l, _, r, _| {
Expr::Pow(Box::new(l), Box::new(r))
}),
infix(left(2), op('*'), |l, _, r, _| {
// prec = 10
prefix(10, op("-"), |_, atom, _| Expr::Neg(Box::new(atom))),
prefix(10, op("!"), |_, atom, _| Expr::Not(Box::new(atom))),
prefix(10, op("~"), |_, atom, _| Expr::BitNot(Box::new(atom))),
// prec = 9
infix(left(9), op("*"), |l, _, r, _| {
Expr::Mul(Box::new(l), Box::new(r))
}),
infix(left(2), just("&&").padded(), |l, _, r, _| {
Expr::And(Box::new(l), Box::new(r))
infix(left(9), op("/"), |l, _, r, _| {
Expr::Div(Box::new(l), Box::new(r))
}),
infix(left(2), op('/'), |l, _, r, _| {
infix(left(9), op("%"), |l, _, r, _| {
Expr::Div(Box::new(l), Box::new(r))
}),
infix(left(1), op('+'), |l, _, r, _| {
// prec = 8
infix(left(8), op("+"), |l, _, r, _| {
Expr::Add(Box::new(l), Box::new(r))
}),
infix(left(1), just("||").padded(), |l, _, r, _| {
Expr::Or(Box::new(l), Box::new(r))
}),
infix(left(1), op('-'), |l, _, r, _| {
infix(left(8), op("-"), |l, _, r, _| {
Expr::Sub(Box::new(l), Box::new(r))
}),
infix(left(1), op('<'), |l, _, r, _| {
// prec = 7
infix(left(7), op("<<"), |l, _, r, _| {
Expr::LShift(Box::new(l), Box::new(r))
}),
infix(left(7), op(">>"), |l, _, r, _| {
Expr::RShift(Box::new(l), Box::new(r))
}),
// prec = 6
infix(left(6), op("<"), |l, _, r, _| {
Expr::LessThan(Box::new(l), Box::new(r))
}),
infix(left(6), op(">"), |l, _, r, _| {
Expr::GreaterThan(Box::new(l), Box::new(r))
}),
infix(left(6), op("<="), |l, _, r, _| {
Expr::LessEq(Box::new(l), Box::new(r))
}),
infix(left(6), op(">="), |l, _, r, _| {
Expr::LessThan(Box::new(l), Box::new(r))
}),
infix(left(1), just("==").padded(), |l, _, r, _| {
// prec = 5
infix(left(5), op("=="), |l, _, r, _| {
Expr::Equals(Box::new(l), Box::new(r))
}),
infix(left(1), just("!=").padded(), |l, _, r, _| {
infix(left(5), op("!="), |l, _, r, _| {
Expr::NotEquals(Box::new(l), Box::new(r))
}),
// prec = 4
infix(left(4), op("&"), |l, _, r, _| {
Expr::BitAnd(Box::new(l), Box::new(r))
}),
// prec = 3
infix(left(3), op("^"), |l, _, r, _| {
Expr::BitXor(Box::new(l), Box::new(r))
}),
// prec = 2
infix(left(2), op("|"), |l, _, r, _| {
Expr::BitOr(Box::new(l), Box::new(r))
}),
// prec = 1
infix(left(1), op("&&"), |l, _, r, _| {
Expr::And(Box::new(l), Box::new(r))
}),
// prec = 0
infix(left(0), just("||").padded(), |l, _, r, _| {
Expr::Or(Box::new(l), Box::new(r))
}),
))
.boxed()
})
Expand Down